The cineraria of florists, which is commonly grown for decorative purposes, is derived from this taxon, of which many varieties and cultivars are known. Its parentage is unknown, but believed to include Pericallis lanata B.Nord., Pericallis cruenta Bolle, and possibly other species. It should not to be confused with true cinerarias derived from the genus Cineraria L. Further confusion with members to the genus Senecio L. to which the common names cineraria or ragwort are applied is also possible.

[Further information available but not yet included in database]

Phagnalon Cass.

About 40 species are found from the Canaries and Mediterranean to central Asia and the Himalayas.

The contact allergenic quinone, 2-(but-2-enyl-3-methyl)-1,4-benzoquinone, has been detected in the following species (Hausen & Schulz 1977a):

Phagnalon atlanticum Ball

Phagnalon rupestre DC.

Phagnalon sordidum Reichb.

See also Phagnalon saxatile Cass.

Phagnalon saxatile Cass.

This species yields 2-(but-2-enyl-3-methyl)-1,4-benzoquinone (Bohlmann & Kleine 1966), the contact allergenic properties of which (Schulz et al. 1968) have been demonstrated in guinea pigs using an open epicutaneous method (Hausen & Schulz 1977a). Strong cross-sensitivity to primin and deoxylapachol was also observed, with weak cross-reactivity to thymoquinone and mansonia quinone A. No cross-reactivity to a number of other quinones, including lapachol and the dalbergiones, could be demonstrated (Hausen & Schulz 1977a).

Picridium crystallinum Sch.Bip.

Desacetylmatricarin (see Matricaria chamomilla L. varrecutita Grierson) and a potentially allergenic guaianolide have been reported from this species.

Picris hieracioides L.

The plant or its oil causes skin eruptions in those who handle it (Towers 1978).

Piqueria trinervia Cav.

Stevia

This Mexican species is used by florists in assembling bouquets; it occasionally causes pollinosis in florists and greenhouse workers (Langley & Sayer 1937).

Porophyllum Guett

About 50 species have been described from warmer regions of the Americas.

α-Terthienyl, a phototoxic thiophene (see Tagetes L. below), has been reported from the following species (Chan et al. 1979, Bohlmann & Zdero 1979):

Porophyllum lanceolatum DC.

Porophyllum ruderale Cass.

Pseudognaphalium obtusifolium Hilliard & B.L.Burtt sspobtusifolium

(syn. Gnaphalium obtusifolium L.)

Rabbit Tobacco, Sweet-Scented Life Everlasting

Referring to Gnaphalium obtusifolium, Remington et al. (1918) noted that preparations of the plant have been applied as a fomentation to bruises.

A 1+ patch test reaction to the "plant oil" from this species in a single patient with multiple allergies was reported by Lovell et al. (1955); similar cases were described by Shelmire (1939a) and by Mackoff & Dahl (1951).

Frain-Bell & Johnson (1979) observed positive patch test reactions to the oleoresin from this species in 6 from 55 patients with the photodermatitis and actinic reticuloid syndrome.

The name black-eyed Susan is also used for a species of Allamanda L. (fam. Apocynaceae).

Rutidosis helichrysoides DC.

In an investigation of "Australian bush dermatitis", two patients from 13 were found to be contact sensitive to this plant and other members of the Compositae (Burry et al. 1973).

Saussurea DC.

The vast majority of the 400 or so species are found in temperate Asia. Odd single species occur in Europe, Australia, and western North America. The genus is classified in the tribe Cynareae.

S. alpina DC., the European species, has scented flowers, an unusual feature in the family Compositae.

Potentially allergenic sesquiterpene lactones have been reported from the following species:

The roots of this plant are the source of the crude drug Radix Aucklandiae or Mu Xiang used in Chinese traditional medicine.

This species provides the fragrance raw materials known as costus oil, costus absolute, and costus concrete. At a concentration of 4% in petrolatum, all three products are active sensitisers, sensitising 25/25, 18/24, and 6/21 human volunteers respectively in a maximisation test (Opdyke 1974, p. 867). Experimental sensitisation of humans to costus oil was described by Marzulli & Maibach (1980). Hydrogenated costus oil failed to sensitise any of 20 volunteers; undiluted costus oil did not have demonstrable phototoxic properties (Opdyke 1974, p. 867). Cheminat et al. (1981a) described the preparation of a poly(aminoethylstyrene) resin with which (Cheminat et al. 1981b) the allergenic sesquiterpene lactones in costus oil may be removed.

An extract of the root was found to have phototoxic activity against three test micro-organisms and also weak antibiotic properties against the two fungal organisms (Wat et al. 1980b).

Costus root oil, at a dilution of 0.01%, produced no positive reactions in 148 patch test screened eczema patients (Rudner 1977). Burry (1980a) observed a strongly positive (3+) reaction to costus root oil in a 75 year old female who had been admitted to hospital with a severe exacerbation of a condition that had been diagnosed 4 years previously as photodermatitis.

Individuals who were contact sensitive to costus absolute showed positive patch test reactions to some other members of the Compositae and other sesquiterpene lactone-containing plants in the families Jubulaceae, Lauraceae, and Magnoliaceae (Mitchell 1974d, Mitchell & Epstein 1974). Thirteen costus-sensitive patients were patch tested with 38 sesquiterpene lactones belonging to five different skeletal classes. Cross-reactivity was observed both to lactones with the same carbon skeleton as the primary sensitiser (costunolide) and to lactones belonging to other classes. An exocylic α-methylene function on a γ-lactone ring was present both on compounds that cross-reacted and on those that did not. The difference between the two groups was that those sesquiterpene lactones giving negative responses were substituted at positions adjacent to the lactone ring (the C6 and/or C8 positions) with more or less bulky groups, and were generally more highly substituted with polar functional groups. It was concluded that such substitution may hinder binding of the reactive methylene group with skin proteins or the actual antigen with an immune receptor (Epstein et al. 1980).

Senecio L.

Members of this genus, which is perhaps the largest in the plant kingdom with its two to three thousand species, are of cosmopolitan distribution. The greatest number of species are to be found in southern Africa and in the Andean region of South America. The genus is classified in the tribe Senecioneae.

Members of the genus typically contain pyrrolizidine alkaloids, many of which can cause irreversible liver damage and also lung tumours when ingested (Smith & Culvenor 1981).

Artemisia stelleriana Besser is also known by the common name dusty miller.

Senecio jacobaea L.

Ragwort, Common Ragwort, Tansy Ragwort

This species was noted as a cause of dermatitis in some persons who handled it (Benson 1973).

Wren (1975) noted that a decoction of the plant has been used in folk medicine as an application to ulcers and wounds; that a poultice made from the herb has been applied to gouty swellings; and that an ointment prepared from the fresh plant has been used for inflammation of the eyes.

Senecio paludaffinis Hilliard

Sesamin, known for its role in sesame oil (Sesamum indicum L., fam. Pedaliaceae) contact dermatitis, has been isolated from this South African species (Bohlmann et al. 1978b).